windows help

ok could someone tell me how to find the stored passwords and user names on a pc ?
ie when you log into a website and the login box appears and you just click ok because earlier you clicked remember login details. where are these stored and are they encrypted and can they be unencrypted ?
I am trying to teach myself all about windows and its security but this one has me stumped i just cant find where they are stored i thought they were pwp files but my pc hasnt got any of those i am running 98.